Abstract of research

MOLECULAR IDENTIFICATION OF SOME CONTAGIOUS MICROORGANISMS CAUSING FOOD POISONING FROM BULK TANK MILK IN GHARBIA GOVERNORATE

Amal, M. Eid

Abstract

This study was conducted to determine the prevalence of food poisoning pathogens in Bulk tank milk from 3 dairy herds in Gharbia Governorate, Egypt. Escherichia coli, Staphylococcal aureus and Listeria monocytogenes were detected in 20, 60, and 10 % in samples collected from farm I , in farm II with percentage of 40, 40 and 20 % and in farm III 20, 20 and 10 % of examined bulk tank milk samples, respectively. Polymerase chain reaction is a powerful technique for detection of pathogens in foods. It is a rapid procedure with both sensitivity and specificity for quick detection and identification of specific pathogenic bacteria from different sources. The eight E. coli isolates were screened for the presence of virulence associated genes (stx1, stx2), heat-stable enterotoxin gene (STa ) and only one (50%) isolate from farm I encoded the STa gene. The ability of Staphylococcus aureus to produce enterotoxins which is linked to Staphylococci enterotoxins SEs genes was investigated by using multiplex PCR, out of 12 Staph. aureus isolated from the examined BTM samples, 2 isolates were carrying sea gene, 1(16.6%) from farm I and 1(25%) from farm II. Listeria monocytogenes detection methods based on PCR amplification of the hly gene sequences specific for confirmation of L. monocytogenes and not any other type of Listeria have been used for identification of all four obtained isolates and the results obtained from isolation were in line with that of molecular diagnosis as PCR detected only the presence of L. monocytogenes. Since presence of these food poisoning microorganisms constitute a potential risk to public health, these findings underscore the need to control them and to limit bacterial multiplication in bulk tank milk.